Heat Exchanger

ABSTRACT

Provided is a heat exchanger in which drainage performance of a tube and a fin is improved while preventing reduction in heat exchange efficiency. The heat exchanger includes: a tube having flat surfaces opposed to each other at a predetermined interval; and a fin including a bent portion and a flat portion which are alternately formed in a longitudinal direction, the bent portion being joined to the opposing flat surfaces of the tube. The fin has a predetermined lateral range (bent portion) in the bent portion which is brought into contact with one of the opposing flat surfaces, the predetermined lateral range being bent toward another of the opposing flat surfaces and joined to the another of the opposing flat surfaces, thereby forming a communication path.

TECHNICAL FIELD

The present invention relates to a heat exchanger, and more particularly, to a fin structure in a heat exchanger.

BACKGROUND ART

Conventionally, heat exchangers have been utilized in, for example, an air conditioning apparatus. The air conditioning apparatus includes, for example, an indoor heat exchanger and an outdoor heat exchanger. It is known that, in the indoor heat exchanger in the case of cooling operation and in the outdoor heat exchanger in the case of heating operation, condensed water is easily generated through dew condensation. The condensed water is liable to accumulate between a tube and a fin of the heat exchanger, which may inhibit an air flow to cause not only reduction in heat exchange efficiency, but also frost formation in the outdoor heat exchanger during heating operation, for example.

To address this problem, as described in, for example, Patent Literature 1, there has been proposed a heat exchanger in which, for drainage of condensed water accumulated in the heat exchanger, a corrugated fin including an inclined portion and a curved portion is joined by brazing between flat heat-transfer tubes (tubes) arranged in a vertical direction, and slits are formed at a plurality of positions in the curved portion of the corrugated fin so as to pass therethrough in the vertical direction.

With such a heat exchanger, it is conceived that, indeed, the condensed water generated through dew condensation on the surfaces of the flat heat-transfer tube and the corrugated fin is guided downward through the slits formed in the curved portion of the corrugated fin.

CITATION LIST Patent Literature

-   [PTL 1] Japanese Patent Application Laid-Open No. 2006-105415 (claim     1, paragraphs [0015] to [0018], FIG. 3)

SUMMARY OF INVENTION Technical Problem

However, the curved portion of the corrugated fin is a part to be joined to the flat heat-transfer tube, and with this contact of this part, heat moves between the flat heat-transfer tube and the corrugated fin. Therefore, when a slit is formed in the curved portion of the corrugated fin as in the heat exchanger described in Patent Literature 1, the contact area between the corrugated fin and the flat heat-transfer tube reduces, and thus the heat exchange efficiency may be lowered.

The present invention has been made as a challenge to solve such a problem described above, and has an object to provide a heat exchanger in which drainage performance of the tube and the fin is improved while preventing reduction in heat exchange efficiency.

Solution to Problem

In order to meet the challenge as described above, according to the present invention, there is provided a heat exchanger, including: a tube having surfaces opposed to each other at a predetermined interval; and a fin including a bent portion and a flat portion which are alternately formed in a longitudinal direction, the bent portion being joined to the opposing surfaces of the tube, in which the fin has a predetermined lateral range in the bent portion which is brought into contact with one of the opposing surfaces, the predetermined lateral range being bent toward another of the opposing surfaces and joined to the another of the opposing surfaces, thereby forming a communication path. Further, the fin is provided with longitudinal cutting lines within the predetermined lateral range of the bent portion so that a part formed by the longitudinal cutting lines is bent toward the another of the opposing surfaces and joined to the another of the opposing surfaces, thereby forming the communication path. Further, the communication path is provided in each of the bent portion which is brought into contact with the one of the opposing surfaces, and the bent portion which is brought into contact with the another of the opposing surfaces. Further, the communication path provided in the bent portion which is brought into contact with the one of the opposing surfaces has a lateral range which overlaps with a lateral range of the communication path provided in the bent portion which is brought into contact with the another of the opposing surfaces.

According to the present invention, it is possible to provide the heat exchanger in which drainage performance of the tube and the fin is improved while preventing reduction in heat exchange efficiency.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic front view of a heat exchanger according to an embodiment of the present invention.

FIG. 2 is a perspective view of a fin of the heat exchanger according to the embodiment of the present invention.

FIG. 3 is a perspective view of a fin of the heat exchanger according to the embodiment of the present invention.

FIG. 4( a) is a plan view of the fin of the heat exchanger according to the embodiment of the present invention.

FIG. 4( b) is a side view of the same.

FIG. 4( c) is a sectional view taken along the line A-A of FIG. 4( a).

FIG. 5 is a perspective view of a fin of a heat exchanger according to another embodiment of the present invention.

FIG. 6( a) is a plan view of the fin of the heat exchanger according to the another embodiment of the present invention.

FIG. 6( b) is a side view of the same.

FIG. 6( c) is a sectional view taken along the line B-B of FIG. 6( a).

FIG. 7 is a perspective view of a fin of a heat exchanger according to further another embodiment of the present invention.

FIG. 8( a) is a plan view of the fin of the heat exchanger according to the further another embodiment of the present invention.

FIG. 8( b) is a side view of the same.

FIG. 8( c) is a sectional view taken along the line C-C of FIG. 8( a).

FIG. 8( d) is a sectional view taken along the line D-D of FIG. 8( a).

FIG. 9 is a configuration view illustrating an example of an air conditioning apparatus including the heat exchangers.

FIG. 10( a) is a schematic view illustrating a modified example of the fin.

FIG. 10( b) is a schematic view illustrating another modified example of the fin.

DESCRIPTION OF EMBODIMENTS

In the following, embodiments of the present invention are specifically described with reference to the drawings. For the sake of convenience, parts having the same action and effect are denoted by the same reference symbols, and description thereof is omitted herein.

First Embodiment

As illustrated in FIG. 1, a heat exchanger 100 includes a plurality of tubes 110 arranged in parallel to each other, through which a refrigerant flows, and fins 120 each joined by brazing between adjacent tubes 110. In the illustrated example, the plurality of tubes 110 are communicated to hollow header tanks 130 and 135 at both ends of the plurality of tubes 110 in their longitudinal direction (refrigerant flowing direction). The header tank 130 provided on the upper side includes a refrigerant entrance portion 130 a provided on one end side, a refrigerant exit portion 130 b provided on the other end side, and a part it ion plate 131 provided at a center thereof, for partitioning inside of the header tank 130. With this, the refrigerant flowing in from the entrance portion 130 a of the header tank 130 flows through the tubes 110 (two tubes on the left side in FIG. 1) communicated on the entrance portion 130 a side with respect to the partition plate 131, and flows into the header tank 135 provided on the lower side. Then, the refrigerant exits from the header tank 135 to flow through the tubes 110 (two tubes on the right side in FIG. 1) communicated on the exit portion 130 b side with respect to the partition plate, and flows out from the exit portion 130 b via the header tank 130. Note that, FIG. 1 schematically illustrates the heat exchanger 100, and is simplified for the sake of easy understanding of the description.

As illustrated in FIG. 2, the tube 110 is formed into a flat hollow plate shape and is made of a metal having high heat conductivity, such as aluminum. Further, in an inside space, a plurality of partition portions 113 are provided so that a plurality of flow paths 111 extending in a longitudinal direction are arranged in parallel in a lateral direction (width direction). As illustrated in FIG. 1, the plurality of tubes 110 are equally arranged in parallel at predetermined intervals so that flat surfaces 115 thereof are opposed to each other, and the fin 120 is joined to the opposing flat surfaces 115 of the adjacent tubes 110. The tube 110 has two longitudinal end portions 110 a and 110 b, which are inserted into insertion holes provided in the header tanks 130 and 135, respectively, and are brazed.

As illustrated in FIGS. 3 and 4, the fin 120 is a so-called corrugated fin, and includes a flat portion 121 having a flat plate shape and a bent portion 122 bent with a predetermined curvature radius, which are formed alternately in the longitudinal direction. The bent portion 122 is a part to be joined to the flat surface 115 of the tube 110, and includes a first bent portion 122 a to be joined to the flat surface 115 of one of the opposing tubes 110, and a second bent portion 122 b to be joined to the flat surface 115 of the other of the opposing tubes 110 (see FIG. 1). In the illustrated example, the flat portion 121 is smoothly and continuously provided to the bent portion 122 (122 a and 122 b) formed into a semi-circular arc shape in cross section. With this, adjacent flat portions 121 are provided in parallel to each other. Further, when the fin 120 is joined to the tube 110, the flat portion 121 becomes perpendicular to the longitudinal direction of the tube 110. Note that, similarly to the tube, the fin 120 is made of a metal having high heat conductivity, such as aluminum.

In a predetermined range (near the center in the illustrated example, and as illustrated in FIG. 4( a), observed as a cutout in plan view) in the lateral direction (width direction) of the first bent portion 122 a, two cutting lines along the longitudinal direction are provided up to an intermediate position of the flat portion 121 continuous with the first bent portion 122 a. Then, the fin within the range of the two cutting lines is bent back from the longitudinal intermediate position of the flat portion 121 so as to be protruded on a side opposite to the side on which the first bent portion 122 a is protruded. In this manner, a third bent portion 122 c is formed. The third bent portion 122 c formed by the two cutting lines extends up to a position of the second bent portion 122 b so as to be joined to the flat surface 115 of the other of the opposing tubes 110.

As illustrated in FIG. 4( b), the third bent portion 122 c has a curvature radius smaller than the curvature radius of the first bent portion 122 a and the second bent portion 122 b, and further, this curvature radius is substantially the same as the curvature radius of a bent-back portion 123 in the flat portion 121. Note that, description is made of an example in which the cutting line has a length extending up to the longitudinal intermediate position of the flat portion 121, but the length may be changed as appropriate so that the third bent portion 122 c can be joined to the flat surface 115 of the other of the opposing tubes 110, depending on the curvature radius of the third bent portion 122 c and the curvature radius of the bent-back portion 123 in the flat portion 121.

As described above, the third bent portion 122 c is formed continuously in the longitudinal direction with respect to the predetermined lateral range of the first bent portion 122 a, and thus a communication path 125 (indicated by an arrow in FIG. 3) is formed along the longitudinal direction of the tube 110 in a predetermined lateral range (width of the third bent portion) on the first bent portion 122 a side. With this, condensed water accumulated inside the fin 120 or between the fin 120 and the tube 110 may be easily drained downward through the communication path 125.

Further, as illustrated in FIG. 1, the first bent portion 122 a is joined by brazing to the surface of the one of the opposing tubes 110, and the second bent portion 122 b and the third bent portion 122 c are joined by brazing to the surface of the other of the opposing tubes 110. With this, the total contact area of the fin 120 with respect to the pair of opposing tubes 110 and 110 is equivalent in both the case where the third bent portion 122 c is provided and the case where the third bent portion 122 c is not provided, and thus reduction in heat exchange efficiency can be prevented.

Second Embodiment

FIGS. 5 and 6 illustrate a fin 220 of a heat exchanger 200 according to a second embodiment of the present invention. Note that, the heat exchanger 200 of the second embodiment has a configuration in which the fin 220 has a structure different from that of the fin 120 of the heat exchanger 100 of the first embodiment. Therefore, description other than that of the fin 220 is omitted herein.

As illustrated in FIGS. 5 and 6, the fin 220 is a so-called corrugated fin, and includes a flat portion 221 having a flat plate shape and a bent portion 222 bent with a predetermined curvature radius, which are formed alternately in the longitudinal direction. The bent portion 222 is a part to be joined to the flat surface 115 of the tube 110, and includes a first bent portion 222 a to be joined to the flat surface 115 of one of the opposing tubes 110, and a second bent portion 222 b to be joined to the flat surface 115 of the other of the opposing tubes 110. In the illustrated example, the flat portion 221 is smoothly and continuously provided to the bent portions 222 a and 222 b formed into a semi-circular arc shape in cross section. With this, adjacent flat portions 221 are provided in parallel to each other. Further, when the fin 220 is joined to the tube 110, the flat portion 221 becomes perpendicular to the longitudinal direction of the tube 110. Note that, similarly to the tube, the fin 220 is made of a metal having high heat conductivity, such as aluminum.

In a predetermined range (near the center in the illustrated example) in the lateral direction of the first bent portion 222 a, two cutting lines along the longitudinal direction are provided up to an intermediate position of the flat portion 221 continuous with the first bent portion 222 a. Then, the fin within the range of the two cutting lines is bent back from the longitudinal intermediate position of the flat portion 221 so as to be protruded on a side opposite to the side on which the first bent portion 222 a is protruded. In this manner, a third bent portion 222 c is formed. The third bent portion 222 c formed by the two cutting lines extends up to a position of the second bent portion 222 b so as to be joined to the flat surface 115 of the other of the opposing tubes 110.

Further, in a predetermined range in the lateral direction of the second bent portion 222 b, which is larger than and overlapped with the range in the lateral direction of the third bent portion 222 c, two cutting lines along the longitudinal direction are provided up to the intermediate position of the flat portion 221 continuous with the second bent portion 222 b. Then, the fin 220 within the range of the two cutting lines is bent back from the longitudinal intermediate position of the flat portion 221 so as to be protruded on a side opposite to the side on which the second bent portion 222 b is protruded. In this manner, a fourth bent portion 222 d is formed. The fourth bent portion 222 d formed by the two cutting lines extends up to a position of the first bent portion 222 a so as to be joined to the flat surface 115 of the one of the opposing tubes 110.

As illustrated in FIG. 6( b), the third bent portion 222 c and the fourth bent portion 222 d have a curvature radius smaller than the curvature radius of the first bent portion 222 a and the second bent portion 222 b, and further, this curvature radius is substantially the same as the curvature radius of a bent-back portion 223 in the flat portion 221. Note that, description is made of an example in which the cutting line has a length extending up to the longitudinal intermediate position of the flat portion 221, but the length is changed as appropriate depending on the curvature radius of the third bent portion 222 c and the fourth bent portion 222 d and the curvature radius of the bent-back portion 223 in the flat portion 221.

As described above, the third bent portion 222 c is formed continuously in the longitudinal direction with respect to the predetermined lateral range of the first bent portion 222 a, and thus a communication path 225 a (indicated by an arrow in FIG. 5) is formed along the longitudinal direction of the tube 110 in a predetermined lateral range (width of the third bent portion 222 c) on the first bent portion 222 a side. With this, condensed water accumulated inside the fin 220 or between the fin 220 and the tube 110 is drained downward through the communication path 225 a. Note that, the fourth bent portion 222 d is arranged so as to block the communication path 225 a, and hence condensed water is drained in a manner that the condensed water threads between the communication path 225 a and the fourth bent portion 222 d.

Further, the fourth bent portion 222 d is formed continuously in the longitudinal direction with respect to the predetermined lateral range of the second bent portion 222 b, and thus a communication path 225 b (indicated by arrows in FIG. 5) is formed along the longitudinal direction of the tube 110 in a predetermined lateral range (width of the fourth bent portion 222 d) on the second bent portion 222 b side. With this, condensed water accumulated inside the fin 220 or between the fin 220 and the tube 110 is drained downward through the communication path 225 b. Note that, the third bent portion 222 c is arranged in the communication path 225 b, and hence only both sides of the communication path 225 b are linearly communicated.

Further, the first bent portion 222 a and the fourth bent portion 222 d are joined by brazing to the flat surface 115 of the one of the opposing tubes 110, and the second bent portion 222 b and the third bent portion 222 c are joined by brazing to the flat surface 115 of the other of the opposing tubes 110. With this, the total contact area of the fin 220 with respect to the pair of opposing tubes 110 and 110 is equivalent in both the case where the third bent portion 222 c and the fourth bent portion 222 d are provided and the case where the third bent portion 222 c and the fourth bent portion 222 d are not provided, and thus reduction in heat exchange efficiency can be prevented.

Third Embodiment

FIGS. 7 and 8 illustrate a fin 320 of a heat exchanger 300 according to a third embodiment of the present invention. Note that, the heat exchanger 300 of the third embodiment has a configuration in which the fin 320 has a structure different from that of the fin 120 of the heat exchanger 100 of the first embodiment. Therefore, description other than that of the fin 320 is omitted herein.

As illustrated in FIGS. 7 and 8, the fin 320 is a so-called corrugated fin, and includes a flat portion 321 having a flat plate shape and a bent portion 322 bent with a predetermined curvature radius, which are formed alternately in the longitudinal direction. The bent portion 322 is a part to be joined to the flat surface 115 of the tube 110, and includes a first bent portion 322 a to be joined to the flat surface 115 of one of the opposing tubes 110, and a second bent portion 322 b to be joined to the flat surface 115 of the other of the opposing tubes 110. In the illustrated example, the flat portion 321 is smoothly and continuously provided to the bent portion 322 formed into a semi-circular arc shape in cross section. With this, adjacent flat portions 321 are provided in parallel to each other. Further, when the fin 320 is joined to the tube 110, the flat portion 321 becomes perpendicular to the longitudinal direction of the tube 110. Note that, similarly to the tube, the fin 320 is made of a metal having high heat conductivity, such as aluminum.

In a predetermined range on one side (in the example illustrated in FIG. 8( a), a predetermined range on the left side with respect to the center) in the lateral direction of the first bent portion 322 a, two cutting lines along the longitudinal direction are provided up to an intermediate position of the flat portion 321 continuous with the first bent portion 322 a. Then, the fin within the range of the two cutting lines is bent back from the longitudinal intermediate position of the flat portion 321 so as to be protruded on a side opposite to the side on which the first bent portion 322 a is protruded. In this manner, a third bent portion 322 c is formed. The third bent portion 322 c formed by the two cutting lines extends up to a position of the second bent portion 322 b so as to be joined to the flat surface 115 of the other of the opposing tubes 110.

Further, in a predetermined range on the other side (in the example illustrated in FIG. 8( a), a predetermined range on the right side with respect to the center) in the lateral direction of the second bent portion 322 b, two cutting lines along the longitudinal direction are provided up to the intermediate position of the flat portion 321 continuous with the second bent portion 322 b. Then, the fin within the range of the two cutting lines is bent back from the longitudinal intermediate position of the flat portion 321 so as to be protruded on a side opposite to the side on which the second bent portion 322 b is protruded. In this manner, a fourth bent portion 322 d is formed. The fourth bent portion 322 d formed by the two cutting lines extends up to a position of the first bent portion 322 a so as to be joined to the flat surface 115 of the one of the opposing tubes 110. Note that, in the illustrated example, the width of the third bent portion 322 c and the width of the fourth bent portion 322 d are equal to each other.

As illustrated in FIGS. 8( b) and 8(c), the third bent portion 322 c and the fourth bent portion 322 d have a curvature radius smaller than the curvature radius of the first bent portion 322 a and the second bent portion 322 b, and further, this curvature radius is substantially the same as the curvature radius of a bent-back portion 323 in the flat portion 321. Note that, description is made of an example in which the cutting line has a length extending up to the longitudinal intermediate position of the flat portion 321, but the length is changed as appropriate depending on the curvature radius of the third bent portion 322 c and the fourth bent portion 322 d and the curvature radius of the bent-back portion 323 in the flat portion.

As described above, the third bent portion 322 c is formed continuously in the longitudinal direction with respect to the predetermined lateral range of the first bent portion 322 a, and thus a communication path 325 a (indicated by an arrow in FIG. 7) is formed along the longitudinal direction of the tube 110 in a predetermined lateral range (width of the third bent portion 322 c) on the first bent portion 322 a side. With this, condensed water accumulated inside the fin 320 or between the fin 320 and the tube 110 is drained downward through the communication path 325 a.

Further, the fourth bent portion 322 d is formed continuously in the longitudinal direction with respect to the predetermined lateral range of the second bent portion 322 b, and thus a communication path 325 b (indicated by an arrow in FIG. 7) is formed toward the longitudinal direction of the fin 320 in a predetermined lateral range (width of the fourth bent portion 322 d) on the second bent portion 322 b side. With this, condensed water accumulated inside the fin 320 or between the fin 320 and the tube 110 is drained downward through the communication path 325 b.

Further, the first bent portion 322 a and the fourth bent portion 322 d are joined by brazing to the flat surface 115 of the one of the opposing tubes 110, and the second bent portion 322 b and the third bent portion 322 c are joined by brazing to the flat surface 115 of the other of the opposing tubes 110. With this, the total contact area of the fin 320 with respect to the pair of opposing tubes 110 is equivalent in both the case where the third bent portion 322 c and the fourth bent portion 322 d are provided and the case where the third bent portion 322 c and the fourth bent portion 322 d are not provided, and thus reduction in heat exchange efficiency can be prevented.

(Usage Example)

As an example in which the heat exchangers (100, 200, and 300) exemplified in the above-mentioned first to third embodiments are used, FIG. 9 illustrates an overall configuration view of an air conditioning apparatus 1 provided in an electric vehicle, for example. This air conditioning apparatus 1 utilizes a so-called heat pump cycle, and switches cooling and heating by switching, with a four-way valve 13, the flow of the refrigerant from a compressor 11 with respect to an out-vehicle heat exchanger 100A and an in-vehicle heat exchanger 100B. Note that, the heat exchanger 100A and the heat exchanger 100B each correspond to any one of the heat exchangers 100, 200, and 300, and in this case, description is made of a case where the heat exchanger 100A and the heat exchanger 100B each correspond to the heat exchanger 100 of the first embodiment.

In the illustrated example, the four-way valve 13 is connected to an ejection port 11 a of the compressor 11. With this, the compressor 11, the in-vehicle heat exchanger 100B, and the out-vehicle heat exchanger 100A are connected as follows. That is, in a case where the four-way valve 13 is connected in a state as indicated by broken lines (heating operation), the refrigerant ejected from the compressor 11 flows into the in-vehicle heat exchanger 100B, and the refrigerant that has passed through the in-vehicle heat exchanger 100B flows into the out-vehicle heat exchanger 100A via an expansion valve 15 so that the refrigerant returns to an intake port 11 b of the compressor 11 via the four-way valve 13. Further, in a case where the four-way valve 13 is connected in a state as indicated by solid lines (cooling operation), the refrigerant ejected from the compressor 11 flows into the out-vehicle heat exchanger 100A, and the refrigerant that has passed through the out-vehicle heat exchanger 100A flows into the in-vehicle heat exchanger 100B via the expansion valve 15 so that the refrigerant returns to the intake port 11 b of the compressor 11 via the four-way valve 13. Note that, a cooling fan 17 is provided adjacent to the out-vehicle heat exchanger 100A.

In an in-vehicle unit of the air conditioning apparatus 1, a damper 21 for intake air switching and a blower 23 are provided on an upstream side of a ventilating duct 20 provided with the heat exchanger 100B. Further, on a downstream side of the ventilating duct 20, a heater unit 25 for heating assistance is provided, and an amount of air passing through the heater unit 25 is adjusted by a damper 27 for discharge air switching. Outlet ports 29 a, 29 b, and 29 c of the ventilating duct 20 are for DEF, FACE, and FOOT, respectively, and dampers 30 a, 30 b, and 30 c respectively provided thereto can adjust the amount of air to be discharged from the outlet ports 29 a, 29 b, and 29 c.

In such an air conditioning apparatus 1, even when condensed water generated through dew condensation adheres to the in-vehicle heat exchanger 100B in the case of cooling operation, the condensed water is drained through the communication path 25 provided in the fin 120 of the heat exchanger 100B. Further, even when condensed water adheres to the out-vehicle heat exchanger 100A in the case of heating operation, the condensed water is drained through the communication path 25 provided in the fin 120 of the heat exchanger 100A.

The embodiments of the present invention have been described above in detail with reference to the drawings, but specific configurations are not limited to those embodiments, and the present invention also encompasses design changes and the like without departing from the gist of the present invention. Further, mutual use of technologies among the above-mentioned embodiments is possible as long as the objects, the configurations, and the like do not have particular contradictions and problems.

For example, description is made of an example in which the plurality of tubes are arranged in parallel, but the present invention is not limited thereto. The present invention is widely applicable to a heat exchanger in which the flat surfaces of the tube are provided opposed to each other, and the fin is arranged between the flat surfaces. For example, the heat exchanger may have a configuration in which one tube is formed into a wave shape so that opposing flat surfaces are formed in the one tube.

Further, description is made of an example in which the adjacent flat portions in the fin are provided in parallel to each other, but the present invention is not limited thereto. For example, as illustrated in FIG. 10( a), adjacent flat portions 421 may be arranged with a predetermined angle. Note that, in the example of FIG. 10( a), each of a first bent portion 422 a and a second bent portion 422 b is provided with a communication path, and condensed water may easily flow into each communication path.

Further, description is made of an example in which the flat portion is provided so as to be perpendicular to the longitudinal direction of the tube, but the present invention is not limited thereto. For example, as illustrated in FIG. 10( b), a position of a bent portion 522 a joined to one of the opposing tubes 110 and a position of a bent portion 522 b joined to the other of the opposing tubes 110 may be more shifted in a vertical direction as compared to the above-mentioned embodiments so that a flat portion 521 is inclined toward the one of the opposing tubes 110. In this case, for example, when the communication path is provided only on the first bent portion 522 a side, if the flat portion 521 is inclined so that the communication path side is always directed downward, the condensed water may easily flow into the communication path.

Further, description is made of an example in which the communication path is provided in a lateral center in the first embodiment and the second embodiment, and the communication paths are provided in both the lateral end portions in the third embodiment, but the present invention is not limited thereto, and the communication path may be provided at any positions. Note that, when the communication path is provided at one lateral end portion, it is known that a larger amount of condensed water adheres to the end portion of the tube on the windward side, and hence it is preferred that the heat exchanger be configured so that air is blown by a fan from the one end side on which the communication path is provided.

Further, description is made of an example in which the bent portion of the fin is curved smoothly with a predetermined curvature radius, but the present invention is not limited thereto. It is sufficient as long as the fin may be joined alternately to the flat surfaces of the opposing tubes. For example, the fin may be completely folded back to obtain corners, and the corners may be used for joining. Alternatively, the fin may be bent to form a rectangular shape for surface joining.

Description is made of an example in which only one communication path is provided in the first bent portion or the second bent portion, but the present invention is not limited thereto, and two or more communication paths may be provided. Further, the width of the communication path described in each embodiment is merely an example, and the present invention is not limited thereto. Each embodiment does not preclude the setting of various widths for the communication path.

Further, each embodiment does not preclude, for example, hydrophilic treatment processing by, for example, a silicate-containing coating on the surface of the heat exchanger. With such hydrophilic treatment processing, condensed water adhering to the fin or the tube easily runs downward, and hence the drainage performance improves.

REFERENCE SIGNS LIST

-   -   100 heat exchanger     -   110 tube     -   115 flat surface     -   120 fin     -   121 flat portion     -   122 a first bent portion     -   122 b second bent portion     -   122 c third bent portion     -   125 communication path     -   200 heat exchanger     -   220 fin     -   221 flat portion     -   222 a first bent portion     -   222 b second bent portion     -   222 c third bent portion     -   222 d fourth bent portion     -   225 a communication path     -   225 b communication path     -   300 heat exchanger     -   320 fin     -   321 flat portion     -   322 a first bent portion     -   322 b second bent portion     -   322 c third bent portion     -   322 d fourth bent portion     -   325 a communication path     -   325 b communication path 

1.-4. (canceled)
 5. A heat exchanger, comprising: a tube having surfaces opposed to each other at a predetermined interval; and a fin including a bent portion and a flat portion which are alternately formed in a longitudinal direction, the bent portion being joined to the opposing surfaces of the tube, wherein the fin has a predetermined lateral range in the bent portion which is brought into contact with one of the opposing surfaces, the predetermined lateral range being bent toward another of the opposing surfaces and joined to the another of the opposing surfaces, thereby forming a communication path.
 6. A heat exchanger according to claim 5, wherein the fin is provided with longitudinal cutting lines within the predetermined lateral range of the bent portion so that a part formed by the longitudinal cutting lines is bent toward the another of the opposing surfaces and joined to the another of the opposing surfaces, thereby forming the communication path.
 7. A heat exchanger according to claim 5, wherein the communication path is provided in each of the bent portion which is brought into contact with the one of the opposing surfaces, and the bent portion which is brought into contact with the another of the opposing surfaces.
 8. A heat exchanger according to claim 6, wherein the communication path is provided in each of the bent portion which is brought into contact with the one of the opposing surfaces, and the bent portion which is brought into contact with the another of the opposing surfaces.
 9. A heat exchanger according to claim 7, wherein the communication path provided in the bent portion which is brought into contact with the one of the opposing surfaces has a lateral range which overlaps with a lateral range of the communication path provided in the bent portion which is brought into contact with the another of the opposing surfaces.
 10. A heat exchanger according to claim 8, wherein the communication path provided in the bent portion which is brought into contact with the one of the opposing surfaces has a lateral range which overlaps with a lateral range of the communication path provided in the bent portion which is brought into contact with the another of the opposing surfaces. 